Artemisinin (Qinghaosu) is a novel sesquiterpene lactone endoperoxide having potent antimalarial activity. Artemisinin is obtained from the leaves of Artemisia annua 1.,the well known traditional Chinese herbal remedy, Qinghao. The only reported method of extraction of artemisinin has been by ethyl ether. Moreover, literature has provided no details of any method of isolation of artemisinin. Investigators working at the Walter Reed Army Institute of Research located Artemisia annua growing in the Washington, D.C. area and reported two procedures for the isolation of artemisinin. One of those procedures depends upon the use of the Ito multi-layer separator extractor. This procedure is only suitable for small scale production. The second procedure, while being capable of producing relatively larger quantities of artemisinin, suffers from major disadvantages, among which is that the procedure depends upon chromatographing a relatively crude fraction on silica gel. This known technique necessitates the use of a large ratio of solute to adsorbent, for example, the order of 1:44. Another disadvantage is that the solvent system used in eluting the chromatographic column is 7.5% ethyl acetate in chloroform, accordingly, the bulk of the eluting system is chloroform which is dense, expensive and unstable. Moreover, the order of elution when using such solvent system is artemisinin (R.pi.0.83), arteannuin B (R 0.72) and the artemisinic (qinghao) acid (R 0.6). The acid being predominant, tends to elute with artemisinin, accordingly the fractions contain large amount of the acid that affects the purity of the desired artemisinin.
It is the principal objective of this invention to provide a simple, practical method for the isolation and recovery of artemisinin from plant material which yields artemisinin in quantities and purity heretofore unobtainable in the methods known in the art.
Still another objective of the invention is the provision of a method for the isolation and recovery of artemisinin which method allows the eluting columns to be reused resulting in enormous savings heretofore impossible using the know methods.